Method of making diaphragms for talking-machines.



W. W. YOUNG. METHOD OF MAKING DIAPHRAGMS FOR TALKING MACHINES.

APPLICATION FILED DEO.1, 1908.

975,668. Patented Nov. 15, 1910.

FIIL 2- WITNESSES: IN VEN TOR.

4 GWMW W A TTORNE Y5 WILLIAM W. YOUNG, O'F SPRINGFIELD, MASSACHUSETTS.

METHOD OF MAKING 'DIAPHRAGMS FOR TALKING-MACHI INES.

Specification of Letters Patent.

Patented Nov. 15, 1910.

Application filed December 1, 1908. Serial No. 465.474.

To all whom it may concern:

Be it known that 1, WILLIAM W. YOUNG, a citizen of the United States ofAmerica, residing at Springfield, in the county of Hampden and State ofMassachusetts, have invented new and useful Improvements in Methods ofMaking Diaphragms for Talking-Machines, of which the following is aspecification.

My invention relates to improvements in methods of manufacturingreproducing diaphragms for talking-machines, and my method consists in ageneral way in thoroughly' impregnating and permeating a suitable, moreor less porous material with a compound, emulsion, or solution whichpossesses the necessary characteristics and qualifications, in impartinga proper surface treatment to such material, in hardening by subjectingthe treated material to heat and pressure, and in raising a portion ofor producing an integral protuberance on the material, the resultingdiaphragm being exceedingly compact, hard, and tough, although thin, andhaving smooth and even surfaces and possessing a uniform thicknessthroughout excepting in the center where the protuberance is located,all as hereinafter set forth.

v The reproducing diaphragms commonly used in talking-machines are madeof mica, or sheet-metal, the mica diaphragms predominating, and owing tothis fact it is not possible to obtain the best results from suchmachines, since neither mica nor simple sheet-metal disks used asdiaphragms are capable of producing such results, moreover, the micadisks or diaphragms are extremely fragile and also expensive because ofthe wasteincidcnt to procuring disks of the proper size, and the primaryobject of my invention is to produce a substitute for mica, sheet-metal,and other kinds of diaphragms, which substitute possesses the necessaryor desirable features outlined in the preceding paragraph, and inaddition is resilient and resonant,'is impervious to moisture andunaffected by climatic changes, and is capable of giving out clear,loud, and distinct tones of great depth and olume, of evenlydistributing the sound waves and quickly, completely, and perfectlyrecovering its stable equilibrium, and of lessening to a great estent,if not eradicating a1together, all alien and discordant noises such asblasts and scratching sounds which are -10 prevalent with the ordinarydiaphragm.

1n the accompanying drawings, which form a part of this application andin which like characters of reference indicate like parts throughout theseveral views-Figure 1 is a side view of a cardboard disk perforated andready for immersion; Fig. 2, a side view of a metallic plate which maybe employed in compressing such disk; Fig. 3,- a side'view of adiaphragm complete, and, Fig. 4, a cross-section, on a large scale, ofsaid diaphragm.

In carrving out my method and producing my diaphragm I make use ofcertain chemical substances or materials which have been found to givesatisfaction, but I do not desire. to be limited to-these particularsubstances-or materials; neither do I desire to be limited to the exactsequence or number of steps in putting said method into practice, sincegood results may be obtained even though some little departure be madein the order or number, or both, of such steps.

Although it is my practice to treat individual disks to produce thediaphragms, it is conceivable that strips or sheets of cardboard orother suitable material might be treated and the diaphragms subsequentlycut out of such strips or sheets.

While it is true that almost any fibrous material or fabric, which issufficiently porous to take up an adequate amount of a filling solution,such as leather, various kinds of paper, or cloth may be used. I findthat a pure, hard-finished bristol-board which is quite thin answersbetter for this purpose than anything else so far tried, provided thesame be perforated before it is subjected to the aforesaid solution. Inthe first view a bristol-board disk 1 is represented, and in this diskis a number of very fine holes 2. The holes 2 are quite numerous andextend through the disk 1 from side to side. One object of theseperforations or holes 2 is to open numerous ways into the interior ofthe disk 1, so as to enable the solution to penetrate and permeate allparts of the disk structure and to become thoroughly and evenlydistributed therein and therethrough, thus insuring after drying andpressing the disk that it will have practically no unfilled portions.Another object of the aforesaid erforations is to afford means forproducmg a diaphragm having a structure of different materials or astructure that is broken up or divided into unlike parts as to texture.I

As a filling for the texture of the disk 1, whether or not said disk beperforated, I prefer to employ one or more minerals mixed with and heldin solution in water by an alkali, together with an inert or neutralmmeral that will mix with water and form with the other solution whencombined therewith a suitable compound, mixture, or emulsion. As thefirst basis for this emulsion I now employ silicate of soda or silicateof potash, and to one of these I add dry oxid of zinc. The resultingmixture or emulsion is particularly adapted for my purpose, since itreadily unites with the disk 1 in a most thorough manner by enteringinto the texture of the same and imparts to such disk when finished andfinally converted into a diaphragm just the properties that arerequired.

After perforating the disk 1, provided this be resorted to, as isgenerally the case, said disk is immersed in the filling emulsion orfiller until thoroughly saturated, next the disk is partially driedeither with or without artificial heat, preferably without, next a drypowder such asoxid of zinc is applied to both sides of the disk, thenthe latter is compressed between two steel plates, then it is subjectedto heat, then it is coated on both sides with some of said filler andpowder is applied as before, then it is partially dried again, as in thefirst instance, then com pressed again, and finally the treated disk isonce more suhrjected to heat until any moisture that mi ht have remainedhas been driven out an the now practically finished diaphragm is hard.Although the diaphragm is substantially in a finished condition, thecoating and the subsequent drying and heating with the intermediatecompressing may be repeated one or more timesas may be deemed necessaryor desirable in order more perfectly to fit said diaphragm for use.During this process a portion of the disk 1 in the center has been leftin a less dense and compact condition, and consequently has-been raisedslightly so that there is a rotuberance 3 in the center of the finisheddiaphragm 4, on one or both sides.

In order to produce the protuberance 3 the plates between which the disk1 is compressed might be made with male and fe male parts like ordinarydies, and then, of course, the raised portion of the disk would be ofthe same density as the other parts, but I prefer to use plates like theone shown at 5, Fig. 2. In this plate 5 it will be noticed there is acentral opening 6, and it is into this opening, or a similar one in theplate on the other side of the disk 1, or in both of such openings, thatthe central portion of said disk expands during the compressingoperation to form the protuberance 3. Thus it will be seen that theprotuberance 3 may be on either or both sides of the diaphragm t, andthat in any event the texture of such protuberance will be less compactor dense and consequentlythicker than that of the surrounding parts,because it is not subjected to pressure like that of said surroundingparts, this difference bein clearly apparent in Fig. 4. The qualities 0the diaphragm are not affected by the position of the protuberance 3 sothat it is immaterial whether said protuberance be on one side or theother of said diaphragm or whether it be upon both sides.

The protuberance, 3 not only reinforces the diaphragm 4:, by assistingin keeping the diaphragm from getting out of shape or warping and at thesame time by increasing the strength, durability, and endurance, of thesame, but enhances the sound reproducing qualities of the diaphragm in amost marked degree, and is especially efficacious in causing the soundwaves to be evenly distributed and the diaphragm to make a quick andperfect recovery thereafter. This protuberance is not built u out ofother materials or parts, but is an mtergral part of the diaphragmitself, therefore it cannot work loose and so produce a rattling soundor blast as it otherwise would be liable to do.

The eifect of the compression between the steel plates, as will be veryreadily understood, is to force the filling into all parts of the disk1, even into the central portion thereof, and to close the perforations2 both with the filling and to some extent with the original texture.The surfaces of the disk are treated, as well as the interior, so thatin the end there is produced a diaphragm which possesses certaincharacteristics that approach thosev of metal, such as hardness,

resiliency, resonance and smoothness. The materials that I use forfilling and coating the disks enter intimately into'the cellularstructure of said disks and thus form a mechanical union therewith, andit is probable that a chemical change also takes place. By followingthis method any number of diaphragms may be produced and all will havethe desired qualifications.

An air drying merely for the first one. that is, the drying after theimmersion of the disk in the filling bath, is generally sufficient, asit is then desired to only partially dry the saturated disk so it can becompressed, and the same is true of all dryings which immediatelyprecede compressing. But the other dryings should be by subjection toheat, for the reasons previously given and for the further reason thatheat tempers the filling and coating material to such an extent and in.such a way as to enhance the resonant qualities of the diaphragm.

What I claim as m invention, and desire to secure by Letters atent, is

1. The method of making diaphragms, for

talking-machines, consisting in introducing as a filler into porousmaterial a deposit from a silicate, an alkali and a neutral'mineral insolution, and in compressing and drying such filled material.

3. The method of making diaph 'agms, for talking-machines, consisting inperforating a piece of fibrous material, in immersing such perforatedmaterial in a filling compound, and in compressing between hard lmporoussurfaces and drying the filled materlal.

4. The method of making diaphragms, for

talking-machines, consisting in immersing porous material in a fillingbath, then In partially drying the material thus treated, then inpowdering such material, then in compressing the same, then insubjecting it to heat, then in coating with the filler and powderingonce more, then in partially drying again, then in compressing again,and finally in subjecting to heat again 5. The method of makingdiaphragms, for talking-machines, consisting in immersing porousmaterial in a filling bath, in compressing such filled material betweenhard plates having openings therein arranged and adapted to afford roomfor the expansion of such portion of the material as is adjacent to suchopenings, and in drying said material.

WILLIAM \V. YOUNG. Witnesses:

F. A. CUTTER, A. C. FAIRBANKS.

